Minor cleanups for nanops#7547

Merged

jreback merged 2 commits intopandas-dev:masterfrom

toddrjen:nanopsclean

Jun 26, 2014

Commits on Jun 23, 2014

additional common.is_*_dtype tests in core.common
toddrjen
committed

Commits on Jun 24, 2014

make better use of dtype tests in nanops
toddrjen
committed